<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body {
      padding-bottom: 700px;
    }

    div {
      background-color: skyblue;
      height: 50px;
      margin: 100px 0;
      position: sticky;
      top: 10px;
    }

    /* div:first-child {
      z-index: 1;
    } */
  </style>
</head>
<body>
  <div>a</div>
  <div>b</div>
  <div>c</div>
  <div>d</div>
  <div>e</div>
  <div>f</div>
  <div>g</div>
  <div>h</div>
  <div>i</div>
  <div>j</div>
  <div>k</div>
  <div>l</div>
</body>
</html>